I'm interested in why the paper did not also include "annihilation - the use of tactical nukes to vaporize a building." Maybe it was vocabulary day in the press pool.

I wonder if someone earlier in the process asked "Is this structural?" and got the answer "Naw, just cut it."

Pretty impressively small debris footprint for an uncontrolled collapse.

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Video of the collapse here:
https://www.miamiherald.com/news/local/community/m...

Clearly wasn’t planned as there were people standing within yards of the building when it came down, one of whom was seriously injured.

That looks like an intentional collapse; there's at least a dozen people standing around all looking in the direction of the building it collapses. It looks like a bulldozer or something similar is pulling on some cables just before the collapse. The street on the opposite side is clearly blocked off in the second video on that page.

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Crazy how slow the guy is to react to the huge building collapsing.
His buddy nopes out of there real quick while the other dude sits there for a second.

Very sad, but RUNNNN damnit.

The equipment had a chain/cable pulling on something when it all came down. You can see it straighten up and lift off the ground.

The injured man certainly didn't look like he expected the building to collapse, standing so close to it - even after the structure began to come down.

He appears to raise his arm in some kind of gesture before beginning to run away.

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Ok. I strike my earlier statement. This certainly was planned and intentional. And stupid.

Is there anything about collapsing an entire building in that tight of a space that is remotely "conventional?"

Quote (Spartan5)

Ok. I strike my earlier statement. This certainly was planned and intentional. And stupid.

I don't believe it was intentional, at least not at that time. There are vehicles parked right next to the property.

Brad

It's all okay as long as it's okay.

Does the demo contractor get paid his full fee?

Dik

It looks pretty intentional to me, there is a hose spray going on and many people lined up on the pavement watching it.

I suppose in essence this wasn't an implosion as there were no apparent explosives involved, but that D9 pulling a central support down.

I think the main building structure collapsed pretty well as intended, but what looks like the central stairwell or lift shaft was a bit more solid and suddenly stands proud of the rest and tips part of the building into the road.

Standing that close does seem nigh on suicidal though.

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Also: If you get a response it's polite to respond to it.

I get the impression that the contractor thought it was going to be a walk in the park. The updated article states that they had issued warnings to neighbors that demolition of building was to commence yesterday morning, so...

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Expecting the collapse or not right at that time, they were doing something pulling with the dozer that was questionable enough they had left the building to watch it happen at a distance.

It also appears they were expecting to eventually drop the building like that based on how the bottom floor had been demolished down to the pillars while the other floors were more complete.

Certainly looked like a "planned implosion", sans explosives. Whatever it was that hit him, his hard hat sure went flying. Any news on his condition?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

In a separate video there is a small chunk that hits his leg and spins him around, followed by what looks like a 3ft by 3ft piece, probably concrete, that sent him flying across the road. It looks like it hit him even with the shoulders on down. I'm a bit surprised it didn't kill him.

Rapid collapses generate truckloads of kinetic energy. I recall seeing a video of an implosion where chunks flew by bystanders that were supposedly at a safe distance. While our skulls are hard, they are not impenetrable.

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Long ago, I worked for a dump-truck company that did a fair bit of demolition like this.
They probably wouldn't have done this job due to the tight surroundings.
But, if more open, weaken it at the bottom and pull at the top.
There was a lot of judgment involved, but NO actual engineering.
So not surprising that something could be done like this, or that it could go wrong.

I have yet to see the vid with the D9 pulling, (not supported formats)
but the phrase

"easier to ask forgiveness than get permission"....Oops

came to me

A few sequenced clips from the video

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Relatively clear video that appears to show heavy equipment pulling supports out immediately prior to the collapse:

https://www.instagram.com/p/Bll9EoHBQ3u/?taken-by=...

I can't help thinking that they were only planning some of the pre-drop work, and weren't expecting the whole building to come down - judging by the number of people allowed to stand within the drop zone, and the lack of any meaningful screens to retain the debris. Maybe they thought they were pulling out a non-load-bearing element, but it turned out to be a critical primary member?

It's pretty remarkable that there was only one significant injury - hope the foreman recovers.

http://julianh72.blogspot.com

hpaircraft - that video suggests there were two others who narrowly missed getting dinged by flying concrete.

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I sure as hell wouldn't want to be in a bulldozer so close to a collapsing building of more than one story. I could be wrong, but those cages can't be built to withstand much more than flying debris hits and the like. Had that building collapsed on top, I imagine that dozer would be significantly shorter right now...

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A ROPS (RollOver Protective Structure) canopy will support the weight of an overturned machine.
Not sure when these were mandated for construction equipment but agricultural equipment has had them for 40 years.

Quote (Wiki)

ROPS legislation was passed in 1975, with OSHA requiring that all tractors manufactured from 25 October 1976 onwards be equipped with ROPS Link

They will take much more than flying debris, but I agree that a tall building may shorten them somewhat.
ps. I have been unable to open any of the videos, but in the pictures that looks like a Tractor-Loader-Backhoe, not a dozer. Confirmation?

Bill
--------------------
"Why not the best?"
Jimmy Carter

or, maybe make them more compact.

Dik

Regarding the guy not running, I sympathize with the guy. I had a project in 2008 where one of the largest cranes in he world collapse on site. I pretty much stood there slack-jawed staring at it until it was well on its way to the ground. It was as though my brain didn't comprehend what was occurring.

My father was a heavy equipment operator who worked with large Caterpillar tractors clearing trees and brush when he worked for the Michigan DNR (Department of Natural Resources) in the 60's and 70's. The Caterpillar tractors had the normal roll-cage primarily to protect the operator from falling limbs and trees and they worked fine. However, one day, while clearing some dead-falls during the winter, due to snow on the ground an unseen section of a tree trunk was being pushed ahead of the tractor blade when it got jammed up against a standing tree and as a result, when the pressure reached a certain point, the log splintered and a three-foot long section of the tree trunk shot up out of the snow and hit my father in the face as there was no frontal guard on the roll-cage. My father had his hard-hat on, but that didn't protect his face. Luckily his injures were limited to facial lacerations and a wrenched neck and shoulder. Anyway, when the accident was investigated by the state they had Caterpillar look at what happened and asked them to suggest modifications. They came up with an add-on shield, made from heavy expanded-metal, that mounted between the frontal braces that tied the top of the roll-cage to the front of engine compartment. Caterpillar added this to their catalogue of options and for awhile at least, they referred to it as a 'Baker Guard'. They even sent a photographer out to one his job-sites after the prototype had been added to his tractor and took a series of photos intended for use by Caterpillar in their brochures. Unfortunately the State of Michigan nixed the idea since the state had a strict policy of non-endorsement of any commercial product or relationship. While Caterpillar never used any of the photos or my father's testimonial, they did give him a set of the pictures which I've got somewhere and if I find them I'll try and post one of them here.

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I am sure that the foreman was focused on his machine operator.
But seeing basketball sized pieces of concrete flying across the road sure does give a view of how many people could have been hurt.

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Bill, I can't tell if it has tracks or not, but it appears to have a loader on the front but no backhoe on the back. So, tracked loader or payloader.

Where did the dozer or loader end up after the collapse?

In one video a red first responder vehicle pulled up on the street within seconds of the collapse. It looked like a rescue or first response truck, similar to an ambulance. Coincidence?

The building was being intentionally collapsed. An off-duty police officer closed the street moments before it happened even though there were no permits to do so. The project manager who was hit by debris has since lost his leg and remains in extremely grave condition.

https://www.miamiherald.com/news/local/community/m...